应用激光, 2011, 31 (3): 215, 网络出版: 2011-10-13
占空比变化对环形激光光内送粉熔池温度场影响研究
Study on The Molten Pool Temperature Filed in Variable Duty Cycle Ring Laser Inside-Beam Powder Feeding
摘要
基于光内同轴送粉激光快速成形工艺, 建立了熔池温度场瞬态有限元模型, 对占空比 K(环形光内外径之比)可变的环形激光光内送粉的熔池温度场的数值模拟表明:占空比的变化对环形激光光内送粉熔池的形状、大小和能量密度分布有很大影2, 00.350.6CCDK取, 对比:各响。在相同工艺参数条件下为、、分别进行单层熔覆实验熔池图像与对应温度场云图结果显示, , contrastCCDimageofmoltenpoolinthecorrespondingtemperaturefieldimage,theresultsshowedthat:theimagesareclosetothenumericalsimulationnephogramsandthendemonstratethatthenumericalsimulationsareright.Experimentsshowthatwhen is0.35, K thecladdinglayersmicrostructureisbetter,thecladdinglayerandthebaseofmetallurgicalcombinationeffectisgood.ringlaserdutycycleinside-beampowderfeedinglasermoltenpooltemperaturefieldKeywords ; ; ; ; 0引言从而影体的融化过程和凝固过程响成形件的壁厚, [45]光内同轴送粉激光熔覆成形工艺具有粉流稳和质量。, , 光粉动态耦合性好粉末利用率定易控发散小本文采用自主研发的光内送粉熔覆成形工艺, , [1]高可以实现绿色制造等优点应用前景广阔, 其装置针对环形激光“占空比可变, 光斑能量分布可, , , Ansys[2]核心在于通过光学变换获得环形中空激光束。环控”的优势运用有限元分析软件, 对变占空比, 探形激光光束作为一种在传播方向上中心光强或轴中空激光光内送粉熔覆熔池温度场进行研究讨, 向光强为零的光束除了功率密度和光束发散角等了占空比的变化对熔池的形状、大小和能量密度分, 、激光束的一般参数外还具有暗斑尺寸环形光束布的影响; 通过熔覆成形过程温度场数值模拟探, , KKdddd占空比( 1/21表示光圈内径2表示光圈讨整个快速原型过程中温度场的变化和分布趋势=, , , [3]外径)等特征参数。在其它工艺参数一定的情况探寻较为理想的占空比范围通过设计三种不同占; 与数下粉气两相流参数和环形光束的占空比变化决定空比的环形光进行光内送粉熔覆实验值模拟, , 了成形过程中熔池内的温度场的变化, 直接影响粉的结果对照比较得出研究结论。为保证激光熔覆,熔池形貌与对应的数值模拟温度场云图比较一致, 从而印证了数值模拟的正确性。实验表明:K为 0.35的环形光所得的熔覆层微观组织较佳, 熔覆层与基体的冶金结合效果较好。
Abstract
Aime d at the process of laser rapid prototyping with inner coaxial powder feeding, the finite element model on the transient temperature field of the molten pool is built and the transient temperature field of the molten pool under the laser with variable duty cycle is simulated numerically. The results show that the duty cycle of the laser affects the shape, dimension and power distribution of the molten pool. In the same process parameter conditions, take K is 0, 0.35 and 0.6 separately single-layer cladding experiment, contrast CCD image of molten pool in the corresponding temperature field image, the results showed that: the images are close to the numerical simulation nephograms and then demonstrate that the numerical simulations are right. Experiments show that when K is 0.35, the cladding layers microstructure is better, the cladding layer and the base of metallurgical combination effect is good.
石皋莲, 石世宏, 吴少华, 李春雷. 占空比变化对环形激光光内送粉熔池温度场影响研究[J]. 应用激光, 2011, 31(3): 215. Shi Gaolian, Shi Shihong, Wu Shaohua, Li ChunLei. Study on The Molten Pool Temperature Filed in Variable Duty Cycle Ring Laser Inside-Beam Powder Feeding[J]. APPLIED LASER, 2011, 31(3): 215.